Good day, @KT_HM. I'll share insights about importing customer lists in QuickBooks Online.
Once you import your customer's data, it's required to enter a customer's name since it's a part of the required field during mapping. This is why the system won't allow you to leave it blank.
In addition, the system won't allow to save an invoice if the customer's field is blank.
As a workaround, I'd suggest looking for a third-party app that would help import your customer's data into QuickBooks. Simply go to the Apps menu and click Find apps. Then, search for the application from there.
Moreover, I'd recommend sending this suggestion to our developers. They can review your request and most likely include it in future updates.
You can always get back to the Community if you have follow-up questions. We're ready to help you out.
